Developer feed tank apparatus



May 19, 1959 w. J. DRUCE DEVELOPER FEED TANK APPARATUS 2 Sheets-Sheet 1Filed April 20. 1954 IvwemTov A Wovmzy S y 19, 1 5 w. J. DRUCE 2,887,029

DEVELOPER FEED TANK APPARATUS Filed April 20, 1954 Q 2 Sheets-Sheet 2United States Patent DEVELOPER FEED TANK APPARATUS William John Druce,Cippenham, Slough, England, assignor to Engelhard Industries Limited,London, England, a British company Application April 20, 1954, SerialNo. 424,474

Claims priority, application Great Britain April 7, 1954 1 Claim. (Cl.95-89) The invention relates to a semi-dry developer unit for use inphoto-contact printing processes of the kind in which a sheet ofsensitized paper after the printing operation is passed for developmentbetween a pair of rollers which take up and carry a film of developingsolution, from a tank.

The invention is of particular application to a method and apparatus ofthe kind described and claimed in the co-pending application of theUnited Kingdom No. 12679/53.

The invention has among its objects to provide a developer unit in whichthe print is evenly wetted over the whole surface in its passage betweenthe rollers of the developer unit; is readily removed in a semi-drycondition after its passage between the rollers, and in which thedeveloper solution is maintained without substantial fluctuation inlevel in the tank of the developer unit.

According to the invention, the developer unit comprises a pair ofrollers mounted in superposed relation with the lower roller in the tankof developer solution and means for controlling the level of liquid inthe tank consisting of a feed tank in communication with the developertank and a cylindrical drum mounted for vertical movement in guides inthe feed tank with a short length of pipe, advantageously provided at amid-position in the length of the drum and projecting both inwardly andoutwardly of the drum, whereby the drum can be filled with the outwardlyprojecting end of pipe directed upwardly and after filling the drumrotated through 180 into the position in which the said end of pipe isdownwardly directed and dips into the liquid in the feed tank.

According to the invention furthermore, lateral holes are drilled inthat length of pipe projecting inwardly into the drum to facilitate evenflow of liquid from the drum to the tank as the level of the liquid inthe tank falls.

According to the invention furthermore, the lower of the two rollers isformed of a hard substance such as rubber and the upper of the tworollers made of a resilient substance such for example as porous rubber,the two rollers being in peripheral contact, so that the sheet ofmaterial to which the developer is to be applied on being passed betweenthe rollers is covered over its entire surface with a thin even film ofdeveloper liquid, and on passing out between the rollers is semi-driedby the pressure exerted between the rollers. Thus it will be understoodthat the roller made of a resilient substance serves to absorb solutionwhich is squeezed out on to the print on being passed in between therollers and, excess liquid absorbed by the roller on the passage of thesheet out.

According to the invention furthermore, an adjacent series of fingersadvantageously made of a plastic material are pivotally mounted toextend across the width of the lower of the rollers with their endsclosely adjacent or lightly in contact with the periphery of the roller,whereby any tendency of the print to stick to the roller is avoided andthe print peeled from the roller.

2,887,029 Patented May 19, 1959 The invention further comprises thefeatures of construction hereinafter described.

The invention is diagrammatically illustrated by way of example in theaccompanying drawings, in which:

Figure l is a plan view of the developer unit;

Figure 2 is a section on the line A--A of Figure 1;

Figure 3 is a section on the line BB of Figure 1;

Figure 4 is a section on the line CC of Figure l; and

Figures 5, 6 and 7 are respectively side elevation, end elevation andplan of a finger.

In carrying the invention into effect according to the constructionillustrated in the drawings, a long developer tank 1 of rectangularsection is supported in brackets 2. Mounted for rotation with the lowerperipheral surface in contact with the liquid in the tank is a lowerroller 3 made of hard rubber. Mounted above and in contact with theroller 3 and slightly out of vertical alignment is an upper roller 4made of a resilient porous substance, such as sponge rubber havingnon-communicating cells. The rollers are of equal length and extendsubstantially the length of the tank 1. The lower roller 3 is rotatableas through a shaft 5 projecting through a slot in one end bracket 2,from a source of power. At the other end, the tank 1 extends through thebracket and is connected as by welding at a midposition at the bottom ofa transversely disposed feed tank 6 of rectangular section.

Eccentrically mounted on a shaft 7 which is adapted for limited rotationis a cylinder 9. The shaft 7 together with the cylinder 9 is mounted inslots 8 formed in the end walls of the feed tank 6. A short pipe 11 ismounted in the lower part of the cylinder 9 so as to project inwardly toa slightly greater extent than outwardly. Diametrically oppositelydisposed pairs of holes 12 are formed in the inwardly projecting ends ofthe pipe 11.

The shaft 7 on which the cylinder 9 is eccentrically mounted is extendedand bent at right angles in such manner as to be adapted to be snappedinto two fixed positions between two pairs of spring arms 13 and 14,these two fixed positions corresponding to the filling position with thepipe 11 upwardly directed and the operative position in which the pipeis downwardly directed, and at to the first or filling position.

Pivotally mounted in series to bear with their ends on the peripheralsurface of the lower roller 3 are fingers 15 made of a plastic substanceand formed to a section to present a rib 16 which is effective toprevent the developer solution collecting on it, and preventing anuneven application of developer to the leading edge of the print onejection from between the developer rollers.

In operation, the sensitized print after being subjected in contact withthe master to a source of light is passed between the rollers 3, 4. Theroller 4 absorbs the developer solution which is evenly smeared over thewhole surface of the print on passing in-between the rollers. Onemerging, the upper roller 4 from which the solution has been pressedout by contact with the hard rubber roller 3, is now effective to absorbany surplus liquid left on the print, which thus issues in a semi-drycondition.

The holes 12 serve to render the automatic feed of the feed tank 6 moresensitive, so that there is substantially no fluctuation in the level ofthe developer liquid in the tank 1.

To fill the cylinder 9, the cylinder is rotated until the projecting endof the pipe 11- is uppermost in which position the end of the shaft 7 issnapped between the spring arms 13 so that the cylinder is held againstmovement during the filling operation. After the filling operation iscompleted, the cylinder is rotated through 180 into the position inwhich the pipe 11 extends vertically downwards and the bent end of thearm of the shaft 7 i is snapped into position between the spring arms14.

I claim:

Feed tank apparatus adapted to be connected to a developer tank forfeeding a liquid supply to said developer tank and maintaining the levelof the liquid in said developer tank, comprising a feed tank for holdingliquid to be fed to the developer tank, a cylinder with sealed endswithin said feed tank mounted for pivotal movement to a filling positionand to an operative feeding position, a short open ended pipe sealedinto the wall of the cylinder to project inwardly and outwardly to thecylinder, the outwardly projecting end of said pipe being adapted in thefeeding position to dip into the liquid in said feed tank to maintainthe level of the liquid in said feed tank which correspondinglymaintains the level of the liquid in the developer tank in communicationwith said feed tank.

References Cited in the file of this patent UNITED STATES PATENTSThornton Jan. 18, Murck Dec. 20, Hall -1 June 27, Murck Sept. 17, NomiyaSept. 13, Lankes et al. Aug. 8, Alink et al. Sept. 12, Debrie Feb. 27,Van Der Grinten May 6, Nagels et a1 Aug. 5,

FOREIGN PATENTS France Jan. 29,

